What Is a Contention Ratio and Why Does It Matter for Business Broadband?
A clear, direct answer to this question — written for UK business owners and IT decision-makers.
Direct Answer
A contention ratio is the number of users sharing the same bandwidth capacity. Business broadband typically has contention ratios of 20:1 to 50:1 — meaning up to 50 businesses share the same connection. A leased line has a contention ratio of 1:1: the bandwidth is dedicated exclusively to your business. For VoIP, cloud applications, or any service where consistent performance matters, 1:1 contention is the only acceptable standard.
Key Points
What you need to know.
The Short Answer
A concise overview of what you need to know.
For UK Businesses
How this applies specifically in the UK context.
Cost Considerations
What to expect in terms of investment and ongoing costs.
Next Steps
What you should do with this information.
Quick Comparison
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Frequently Asked Questions
Residential broadband is usually contended at 50:1, meaning up to 50 premises share the same backhaul capacity. Business broadband improves this to around 20:1, but speeds still drop noticeably during peak hours. UK broadband average download speed is 69.4 Mbps (Ofcom Connected Nations 2024), but that average masks significant variation caused by contention, particularly between 9am and 5pm when business demand peaks.
Voice and video traffic is highly sensitive to contention because it requires consistent low-latency delivery. On a contended connection, other users' traffic can cause jitter and packet loss that degrades call quality. A leased line's 1:1 contention ratio eliminates this problem entirely. A leased line typically delivers 99.99% uptime SLA (industry standard), making it the recommended foundation for businesses relying on real-time communications.
For businesses running VoIP, cloud-hosted applications, or services where consistent performance directly affects revenue or productivity, 1:1 contention is worth the premium. The monthly cost difference between a contended broadband line and an uncontended leased line has narrowed considerably in recent years. For offices with fewer than ten users and no VoIP, a well-provisioned business broadband connection may still be adequate.
Related Questions
Leased Line vs Broadband
How 1:1 contention on a leased line compares to shared broadband for business use.
Leased Lines
AMVIA's managed leased line service — dedicated, uncontended connectivity for UK businesses.
Business VoIP
VoIP performance depends on consistent bandwidth — a 1:1 contention leased line is the recommended foundation.
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